Motors of this kind are often extremely small, and can have, for example, an outside diameter of less than 2 cm. They are preferably used to drive small fans for direct cooling of the processor in computers, and since only very limited space is available on a computer circuit board, a low overall height for such motors is desirable; their operation must nevertheless be absolutely reliable.
A motor known from EP 766 370 A2 and corresponding U.S. Pat. No. 5,831,359, JESKE, has a relatively large overall height, since in it, the interaction of the permanent magnet of the external rotor and the claw pole arrangement of the interior stator must generate on the rotor a magnetic pull which ensures that the shaft is pressed with sufficient force onto the axial bearing. For this purpose, in this motor the rotor and stator must be highly offset in the axial direction.
It is therefore an object of the invention to make available a new claw pole motor, in particular a subminiature motor, that is suitable, for example, as a fan drive system for cooling microprocessors.